Maths for throw out

tofferson

Regular Member
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I've measured the run out of my front hub on my Astra g 2.2 I've taken the reading from the outer most point of the face and the run out is 0.05mm, does anyone no what this would equate to at the outer most point of the face of a 320mm disc?
 
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tofferson

Regular Member
Ha ha I forgot to measure it lol was hoping someone would no on here
I've fitted a new disc and have a run out of 0.20 and was thinking it may be hub At fault not the disc, everything went on clean, I'm guessing when the diameter doubles so does run out or is it the radius, or I could be compleatly wrong.
 
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tofferson

Regular Member
Ok not been on for a while needed some time off my car as it was wrecking my head, got back on it today and it still wrecks my head.
I've got a horrible stering wheel vibration above 60 when braking and when braking at very slow speed like pulling up it feel like abs in slow motion the car is jerking when braking.
This has started when I replaced the discs and pads and I cannot find the issue the things I've done so far are
Isolated it to osf wheel by clamping it off with molgrips then problem goes,
I've got new braided lines to go on so wasn't bothered about clamping old hose
I've checked runout at top and bottom of disc on both sides carnt check middle due to them been groved, runout is fine
Had a bit of play in bearing so fitted a new one,
Calipers are refurbed and compleatly free

When I spin wheel the disc has a slight tight spot but no idea why,
Don't no if a week caliper Spring could have anything to do with it
Any help would be apretiated cheers
 

HarleyPete

Senior Member
Firstly check that the mating surfaces are clean. If there is some rust/debris/dried up grease that could cause the disc to run out. It is entirely possible that your new discs are slightly bent to. Can't see it being the caliper as it would rub all the time. Did you re-grease slid pins on the calipers. Sounds very much like the discs are either warped from new or not sitting square against the hub. Steering vibration could also be tracking or wheel bearings. Failing that it could be an abs fault but hopefully not.
 

tofferson

Regular Member
Firstly check that the mating surfaces are clean. If there is some rust/debris/dried up grease that could cause the disc to run out. It is entirely possible that your new discs are slightly bent to. Can't see it being the caliper as it would rub all the time. Did you re-grease slid pins on the calipers. Sounds very much like the discs are either warped from new or not sitting square against the hub. Steering vibration could also be tracking or wheel bearings. Failing that it could be an abs fault but hopefully not.
Hi Pete I've checked everything and all seems well and the run out is fine too, but I still believe it's the disc I've sent it for a light skin to see if it solves the problem
 

HarleyPete

Senior Member
Skimming it will take out any slight imperfections but obviously will reduce it's service limit in comparison to the other dis. Let's hope it sorts it out mate.
 
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